Valve seat grinding device



J. 12, 1943. J sMlTH 2 VALVE SEAT GRINDING DEVICE Filed Feb. 24, 1941 6 H 1, J wz w INVENTOR. Q I

ATTORNEY 5 Patented Jan. 12, 1943 UNITED STATES '5 OFFICE VALVE? SEAT GRINDING DEVIEE Application February 24, 1941, Serial No. 380,264

6, Claims,

This invention relates to the art of grinding valve seats; and is. particularly directed tomechanism adapted for use in the original grinding or the regrinding of the valve seats of internal combustion, engines. In the performance of this operation of grinding a valve seat, it is of prielement; namely, the. pilot rod. It also had the fault that no provision was made for reducing the friction between the pilot rod and. the guide sleeve for the valve stem. Moreover, despite this pilot rod, a certain amount of lateral spring was permitted at the region; of the grinding stone so that the seatsv were not absolutely and uniformly accurate. The normal distancefrom the top of the boss, within whichth guide sleeve is disposed to the plane of the valve seat was suincient to permit this lateral springing due to. the speed of" the rotation and the weight of the drive ing means. employed. Quite obviously, the slightest unbalance of the mass of the driving means or looseness of the parts sets up a wobble in the drive.

In other words, it may be said that the valve stem guide sleeve of the average internal combustion engine did not provide support close enough to the valve seat, and this fault existed not only because of its spacing from the valve seat, but because of its length.

It has been the object of; the present inventor to provide a valve grinding device wherein there is no necessity for the use of a pilot. Stated more specifically, the present inventor has provided an arrangement of the drive shaft wherein it extends upwardly through the guide sleeve and carries the grinding stone on its upper end, thus, constituting in one sense the pilot rod, or in another sense, eliminating it.

Furthermore, it has been an object of the present inventor to provide a device of this character wherein there is little or no opportunity for lateral displacement of the grinding stone, for it is sufficiently supported by a bearing means extended relatively close to the plane of the valve seat and above the normal plane of the valve guide sleeve. Asa part of, this same general objective, it has been the further purpose of the present inventor to increase the length of the supporting means and, at the same time, to reduce as much as possible the friction between the driving shaft and the guide sleeve.

Obviously, this presents problems in the insertion and mounting of the anti-friction means. These problems have been solved by the provision of separate elements insertable from below and from above, which elements rest against the ends of the bearing sleeve and are easily inserted and extracted for the performance of thevalve grind-. ing operation.

The inventor has further provided a coupling means for attaching a power device to the shaft of the grinding stone so that pressure may be applied to the grinding stone adequate for grinding the. hard valve seat.

Other objects and certain advantages of the invention will be more fully apparent from the following description of the drawing in which:

The figure is a sectional view taken through a cylinder block on the axis of a valve seat and valve guide, showing the grinding deviie of this invention in position.

An embodiment of the invention, therefore, provides a device which has the driving shaft carrying the grinding stone on its upper end and extending downwardly through the guide sleeve for the valve stem. The driving attachment is at the lower end of the shaft. Inserts are utilized, incorporating bearings for the purpose of extending and more efficiently distributing the bearing for the shaft. In View of the fact that these devices must be quickly mounted for the grinding operation, the bearing units are conveniently insertable and removable.

Referring to the drawing, a conventional cylinder block for an internal combustion engine is indicated at i. Only enough section of the block is shown to illustrate the environment of one valve. The valve seat 2. is formed of, hardened metal and is countersunk in the top surface of the cylinder block in a circular recess 3. The guide sleeve 4 for the valve stem is fixed in a bore in a boss 5 of the block below the seat coaxially of the seat. This described structure constitutes the complete environment of the grinding device before the valve is in place or after it has been removed.

The grinding stone 6 provides an inclined grinding edge 1 formed at the correct inclination for the particular valve seat. The upper end of the shaft 8 provides a shoulder 9 and a screwthreaded portion. In projecting above the shoulder. Flange collars Illl are provided above and below the grinding stone. The lower flange collar is countersunk in the grinding stone in a circular recess I2. The screw-threaded portion of the shaft loosely traverses the bore of the grinding stone, and the respective flange screwed upon the screw-threaded portion clamps the stone in position between them and upon the shoulder 9 of th shaft.

The shaft 8 is of lesser diameter than the bore l3 of the guide sleeve 4 in order to provide sufficient clearance between the shaft and the bore. A coupling element I4 is screwed on the lowered end of the shaft against the shoulder l 5 thereof. This coupling provides a cross pin l6 permitting the drive shaft (not shown) of the driving means to be hooked thereto for driving and a downward thrust imposing connection of the driving medium thereto.

The bearing arrangement utilized in relation to the guide sleeve and the shaft consists of two units. These units are duplicates and need only be described in the singular. They are inserted respectively from above and below the guide sleeve and project into it, substantially abutting at an intermediate point in the guide sleeve. Each unit consists of a sleeve l1 providing an insertable extension l8 and a head IS. A ball bearing 20 is mounted in a circular recess in the head of each sleeve. The ball bearing is held in place by means of a plug 2! screw-threaded into the end of the head for holding the outer race of the bearing against the shoulder at the base of the recess. The shaft fits snugly through the bores 22 of the sleeve extensions projecting into the guide sleeve in order to prevent lateral springing of the shaft. An intermediate bearing may be used if desired.

Each sleeve extension I8 includes an unfinished peripheral groove 23 medially of its length between a finished section 24 at its inner end, which fits snugly into the bore l3 in the valve stem guide sleeve, and a slightly tapered section 25 at its outer end for centering the insert axially in the guide sleeve 4.

Thus, it will be seen that the heads of the bearing units extend above and below the normal valve guide and thus, extend the bearing surface for increased support of the drive shaft. Also, the upper one raises the bearing assembly above the normal guide sleeve and closer to the valve seat being ground. The shaft 8, as stated, pilots the grinding stone, and there is no necessity for the extra pilot element found in the prior structures.

Having described my invention, I claim:

1. A valve seat grinding device, comprising a grinding stone, a drive shaft for said grinding stone having the grinding stone fixed on its upper end, said shaft adapted to be inserted through the guide sleeve of the valve stem, bearing units insertable into said guide sleeve from above and below the guide sleeve and containing anti-friction elements, said drive shaft supported in said elements, and means for coupling a driving means to the lower end of said shaft.

2. A valve seat grinding mechanism, comprising a drive shaft, a grinding stone fixed to the upper end of the drive shaft, and a driving coupling at its lower end, said shaft adapted to traverse the bore of the valve guide sleeve and being of lesser diameter than the bore of said sleeve, and bearing sleeves inserted in the valve guide sleeve about the shaft and providing antifriction bearings for said shaft, said bearing sleeves extending above and below the upper and lower ends of the valve guide sleeve.

3. A valve seat grinding mechanism for grinding the valve seat of an internal combustion engine which includes a valve guide sleeve coaxial with the valve seat, a shaft extended upwardly through the valve guide, a grinding stone fixed on the upper end of the shaft in the general plane of the valve seat for grinding said seat, upper and lower bearing sleeves disposed in the valve guide and about the shaft, said bearing sleeves projecting upwardly and downwardly beyond the valve guide and including head portions, in which are mounted anti-friction bearings for supporting the shaft above and below the valve guide, and means for coupling said shaft to a drive means. I

4. A valve seat grinding mechanism for grinding the valve seat of an internal combustion engine which includes a valve guide sleeve coaxial with the valve seat, a shaft extended upwardly through the valve guide, a grinding stone fixed on the upper end of the shaft in the general plane of the valve seat for grinding said seat, upper and lower bearing sleeves disposed in the valve guide and about the shaft, said bearing sleeves projecting upwardly and downwardly beyond the valve guide for journalling the shaft above and below the valve guide, and means for Coupling said shaft to a drive means.

5. A valve seat grinding device, comprising a grinding stone, a drive shaft for said grinding stone having the grinding stone fixed at its outer end, said shaft adapted to be inserted through the guide sleeve of the valve stem, a bearing means adapted to be inserted into the guide sleeve for the valve stem, said bearing mean including a portion adapted to extend beyond the valve stem toward the grinding stone so as to provide adequate support for that portion of the shaft extended between the end of the guide sleeve and the grinding stone, and means for coupling a driving means at the lower end of said shaft.

6. A valve seat grinding attachment consisting of a drive shaft, a grinding stone fixed to the 

